DE2651505C2 - - Google Patents

Description

Aqueous dispersions of polyurethanes or polyurethaneureas have long been known cf. z. B. Applied Chemie, 82 (1970), pages 53 to 63; DE-OS 23 14 512 or 23 14 513, and have a high level of quality.

Not least the fact that many of these dispersions are free from emulsifiers, contributes to this high Level at. They contain incorporated by chemical means hydrophilic centers, the self-emulsifying the otherwise cause hydrophobic elastomers.

The in the known, water-dispersible polyurethanes or polyurethane materials incorporated hydrophilic Centers can be both salt-like, d. H. ionic Represent groups as well as hydrophilic nonionic groups.  

The former "polyurethane ionomers" include both chemically fixed cations, d. H. especially chemically built-in ammonium ion-containing polyurethanes as well as chemically fixed anions, d. H. in particular incorporating sulfonate or carboxylate groups Polyurethanes. To the latter nonionic, in Water-dispersible polyurethanes are in particular having the pendant polyethylene oxide chains Polyurethanes or polyurethane ureas according to DE-OS 23 14 512 and 23 14 513.

The dispersions of these polyurethanes, depending on Type of hydrophilic center different characteristic Property photos. So are polyurethane ionomer dispersions, since the salt groups contained in them practically not temperature-dependent in their solubility are stable against heating to boiling, non-ionic On the other hand, dispersions already coagulate on heating at medium temperature (about 60 ° C), since the polyethylene oxide Side chains at higher temperature their Gradually lose solubility in water. In contrast to ionomers, however, these dispersions are against the addition virtually unlimited amounts of electrolyte resistant and stable even after freezing and thawing.

The sensitivity to electrolytes is included cationic polyurethanes are particularly large. In water dispersed polyurethanes with quaternary ammonium or tertiary sulfonium groups coagulate immediately, even  if only very small amounts of an electrolyte with monovalent ions, such as sodium chloride, in aqueous Solution can be added. Because of this property is the preparation and use of cationic polyurethane dispersions associated with special problems. So must be used for the production of water in the rule which is largely free of ions. "Hard" Water leads to an undesirable coarsening of dispersed particles or for partial coagulation.

The pigmentation of cationic dispersions designed often difficult as it absorbed on the pigment surface Ions complicate the incorporation of the pigments and inhomogeneities. The extraordinary Sensitivity of cationic polyurethane dispersions opposite additives of the most different kind has the technical use very difficult or even impossible made. On the other hand, cationic dispersions particularly desirable properties, for. Very much good adhesion to various substrates and a excellent filming ability even at high hardness of the coatings.

The invention now dispersible in water cationic polyurethanes provided in Form of their aqueous dispersion both the advantage of excellent frost and electrolyte resistance as also the advantage of a very good temperature resistance respectively. As it was surprisingly found succeeds in the preparation of such water-dispersible  cationic polyurethane elastomer then when in the polyurethane is both pendant or terminal Ethylene oxide units having hydrophilic chains as also cationic groups are incorporated.

This is quite surprising, as it turned out that mixtures of aqueous dispersions ionic and nonionic polyurethanes by no means such Combination of desirable properties. Rather, such mixtures are more particularly those Disadvantages of the individual components.

By incorporating hydrophilic polyether segments either at the ends of the polymer backbone or in the form of Side chains become surprisingly effective Protection of cationic polyurethanes over the Effect of electrolytes achieved. The dispersions do not become dilute sodium chloride solution anymore like.

Compared to products where the hydrophilic polyether segments statistically over the entire polymer backbone are distributed, the dispersions are distinguished according to the invention by a particularly favorable rheological Behavior off. The dispersed particles are only moderately and essentially only swollen in the marginal zone, so that a favorable relation of solids content the dispersion and its viscosity is achieved. 40% dispersions are still well flowing.  

The invention relates to a process for the preparation of water-dispersible polyurethanes with im essentially linear molecular structure by reaction of organic diisocyanates in the sense of Isocyanatpolyadditionsreaktion difunctional, terminal isocyanate-reactive hydrogen atoms containing organic compounds of the molecular weight range 300 to 6000 under co-use from both

• a) dispersions and / or in the sense of Isocyanatpolyadditionsreaktion difunctional compounds with isocyanate-reactive hydrogen atoms and with pendant ethylene oxide units having hydrophilic chains in one such amount that in the final polyurethane 2 to 10 wt .-% of lateral ethylene oxide units exist as well
• b) mono- or diisocyanates and / or in the sense of Isocyanatpolyadditionsreaktion mono- or difunctional Compounds with opposite isocyanate groups reactive hydrogen atoms with ionic Groups or convertible into ionic groups Groups,
• the at least partial transfer of the the latter groups in hydrophilic groups during or subsequent to the polyaddition reaction carried out, as well as possibly under co-use  the known in polyurethane chemistry Chain extender of one under 300 lying molecular weight in an equivalent ratio from isocyanate groups to isocyanate groups reactive groups of 0.8: 1 up to 2.5: 1 and, if appropriate, with joint use the usual in polyurethane chemistry auxiliary and Additives, characterized in that
• i) optionally in place of or together with the diisocyanates or the difunctional compounds with isocyanate-reactive Hydrogen atoms with pendant ethylene oxide units having hydrophilic chains, monoisocyanates having ethylene oxide units hydrophilic chains and / or in the sense of Isocyanatpolyadditionsreaktion monofunctional compounds with isocyanate-reactive Hydrogen atoms with ethylene oxide units having hydrophilic chains in such Amount used in the final polyurethane 2 to 10 wt .-% terminally incorporated or 2 to 10% by weight incorporated laterally or terminally Ethylene oxide units are present, and that one
• ii) the type and amount or the degree of neutralization or quaternization of component b) is such that in the final polyurethane obtained from 16 to 100 milliequivalents per 100 g

For the inventive method suitable organic Diisocyanates are those of the general formula R (NCO) ₂, where R is an organic radical as defined by Removal of isocyanate groups from an organic Diisocyanate of the molecular weight range 112 to 1000, preferably from 140 to 400. Especially preferred for the inventive method suitable Diisocyanates are those of the indicated general Formula in which R is a divalent aliphatic Hydrocarbon radical having 4 to 18 carbon atoms, a divalent cycloaliphatic hydrocarbon radical with 5 to 15 carbon atoms, one divalent aromatic hydrocarbon radical with 6 to 15 carbon atoms or an araliphatic one Hydrocarbon radical having 7 to 15 carbon atoms stands. Typical representatives of for the invention Process preferred suitable organic diisocyanates are z. Tetramethylene diisocyanate, hexamethylene diisocyanate, Dodecamethylene diisocyanate, cyclohexane-1,3- and 1,4-diisocyanate, 1-isocyanato-3-isocyanatomethyl-3,5,5- trimethylcyclohexane, 4,4'-diisocyanatodicyclohexylmethane or aromatic diisocyanates, such as 2,4-diisocyanatotoluene, 2,6-diisocyanatotoluene, from these isomers existing mixtures, 4,4'-diisocyanatodiphenylmethane and 1,5-diisocyanato naphthalene.

For the inventive method suitable in the sense the isocyanate polyaddition difunctional, terminal, having isocyanate groups reactive groups  Compounds of the molecular weight range of 300 to 6000, preferably from 500 to 3000, are in particular

• 1. the known in polyurethane chemistry Dihydroxypolyester from dicarboxylic acids, such as succinic acid, Adipic acid, suberic acid, azelaic acid, sebacic acid, Phthalic acid, isophthalic acid, terephthalic acid and tetrahydrophthalic acid, and diols, such as z. As ethylene glycol, propylene glycol-1,2, propylene glycol 1.3, diethylene glycol, 1,4-butanediol, hexanediol 1,6, octanediol-1,8, neopentyl glycol, 2-methylpropanediol 1,3, or the different isomers cyclohexanes bis (hydroxymethyl);
• 2. the known in polyurethane chemistry polylactones such. B. starting on the mentioned under 1. dihydric alcohols polymers of ε- caprolactone;
• 3. the known in polyurethane chemistry Polycarbonates, as by reaction, for example the diols mentioned under 1, with diaryl carbonates or phosgene are available;
• 4. the known in polyurethane chemistry Polyether, such as. B. using bivalent Starter molecules, such as water, the lower than 1. having diols or 2 NH bonds  Amines produced polymers or copolymers styrene oxide, propylene oxide, tetrahydrofuran, Butylene oxide or epichlorohydrin. Also, ethylene oxide can be used proportionally with the proviso that the polyether used contains at most about 10 wt .-% of ethylene oxide. In general, however, such polyethers are used without the concomitant use of ethylene oxide were obtained;
• 5. the known in polyurethane chemistry Polythioether, polythiomic ether, polythioetherester;
• 6. the known in polyurethane chemistry Polyacetals, for example from those mentioned under 1. Diols and formaldehyde; such as
• 7. difunctional, terminal, towards isocyanate groups reactive polyetheresters.

Dihydroxypolyesters, Dihydroxypolylactones, dihydroxypolyethers and dihydroxypolycarbonates used.

As in the inventive method for producing the self-dispersible polyurethanes to be used Chain extender of a lower than 300 Molecular weight, for example, in the production  the dihydroxy described low molecular weight Diols or diamines, such as diaminoethane, 1,6-diaminohexane, piperazine, 2,5-dimethylpiperazine, 1- Amino-3-aminomethyl-3,5,5-trimethylcyclohexane, 4,4'- Diaminodicyclohexylmethane, 1,4-diaminocyclohexane, 1,2- Propylenediamine or hydrazine, amino acid hydrazides, Hydrazides of semicarbazidocarboxylic acids, bis-hydrazides and bis-semicarbazides.

In addition to those mentioned in the sense of Isocyanatpolyadditionsreaktion difunctional structural components can in special cases, in which a branching of the Polyurethanes is desired, even in polyurethane chemistry known trifunctional and higher functional Components are partially shared. This is particularly advantageous when monofunctional hydrophilic polyether can be used. The middle However, functionality of the structural components should preferably 2.1 does not exceed.

In the method according to the invention, as hydrophilic Building components both ionic and nonionic in the sense of the isocyanate addition reaction both mono- as well as difunctional compounds are used; in fact

• a) diisocyanates and / or in the sense of Isocyanatpolyadditionsreaktion difunctional compounds with isocyanate-reactive hydrogen atoms and with pendant ethylene oxide units  having hydrophilic chains and / or Monoisocyanates having ethylene oxide units hydrophilic chains and / or in the sense of Isocyanatpolyadditionsreaktion monofunctional compounds with isocyanate-reactive Hydrogen atoms with ethylene oxide units having hydrophilic chains and
• b) any mono- or diisocyanates and / or in the sense the isocyanate polyaddition reaction mono- or difunctional Compounds with opposite isocyanate groups reactive hydrogen atoms with cationic groups are used.

Among the preferred bifunctional hydrophilic structural components with pendant ethylene oxide units having hydrophilic chains include both compounds the general formula

and / or compounds of the general formula  

Particularly preferred structural components a) are those the first general formula (I).

In the general formulas (I) and (II) stand
R is a divalent radical, as obtained by removal of the isocyanate groups from a diisocyanate of the formula R (NCO) ₂ of the aforementioned type,
R 'is hydrogen or an inferior hydrocarbon radical having 1 to 8 carbon atoms, preferably hydrogen or a methyl group,
R '' is a monovalent hydrocarbon radical having 1 to 12 carbon atoms, preferably an unsubstituted alkyl radical having 1 to 4 carbon atoms,
X for a polyalkylene oxide chain having 5 to 90, preferably 20 to 70 chain members which at least 40%, preferably at least 65% of ethylene oxide units and which consist of ethylene oxide units of propylene oxide, butylene oxide or styrene oxide units, wherein among the latter units propylene oxide units are preferred,
Y is oxygen or an -NR '''- radical, wherein R''' in its definition corresponds to R ''.

The preparation of the compounds of the above general formulas (I) and (II) can be prepared according to Procedures of DE-OS 23 14 512 and 23 14 513 be made, where supplemented there revelation It should be noted that instead of there as a starting material mentioned monofunctional polyether alcohols it is also possible to use those whose polyether segment except ethylene oxide units also up to 60% by weight, based on the polyether segment, of propylene oxide, Butylene oxide or styrene oxide, preferably propylene oxide Have units. The proportion of such "mixed polyether segments" can be used in special cases specific benefits.

Further particularly preferred hydrophilic structural components for installation of terminal or lateral hydrophilic ethylene oxide units containing chains are compounds of the formula

H-X-Y-R ''

and / or compounds of the formula

OCN-R-NH-CO-X-Y-R ''

in which
X, Y, R and R "have the meaning explained for the general formulas (I) and (II).

Preferably, however, monofunctional polyethers become only in molar amounts of ≦ 10%, based on the used Polyisocyanate used to produce the desired high molecular weight To ensure construction of the polyurethane elastomers. When using larger molar amounts of monofunctional Alkylenoxidpolyethern is the concomitant use of trifunctional isocyanate-reactive Hydrogen-containing compounds of advantage, however, the average functionality of the build components is supposed to be (Polyisocyanates and polyhydroxyl compounds) preferably not exceed 2.1.

The preparation of the monofunctional hydrophilic structural components takes place in analogy to the DE-OS 23 14 512 or 23 14 513 or in US-PS 39 05 929 or 39 20 598 described method by alkoxylation a monofunctional starter, such as. B. n-butanol or n-methyl-butylamine, using ethylene oxide and optionally a further alkylene oxide, for. For example, propylene oxide, and optionally other, but less preferred, Modification of the monovalent so available Polyether alcohols by reaction with excess Amounts of diisocyanates or by reaction with ammonia to the corresponding primary aminopolyethers.  

Essential components of the invention b) are preferably in the sense of the isocyanate polyaddition reaction mono- or difunctional compounds with built-in tertiary amine nitrogen atoms, which after completion of construction of the polyurethane by quaternization and / or neutralization converted into the corresponding ammonium ions become. Examples of such compounds are in US-PS 34 79 310, column 4, lines 11 to 62, mentioned. Suitable neutralizing or quaternizing agents are, for example, in the US patent in column 6, lines 14 to 25, called.

For incorporation of less than the ammonium groups preferred tertiary sulfonium groups in the polyurethane For example, in US-PS 34 19 533, column 3, line 75, to column 4, line 51, listed compounds used as structural components.

In the method according to the invention, the type and amount the components a) chosen so that in the inventive Polyurethanes 2 to 10, preferably 4 to 8% by weight of side or terminal ethylene oxide Units -CH₂-CH₂-O- present. The kind and Quantity or the degree of neutralization or quaternization the components b) is used in the process according to the invention chosen so that in the polyurethanes of the invention 16 to 100 milliequivalents per 100 g, preferably 16 to 40 milliequivalents per 100 g an = N⊕ =,

available. Preferably lies  the sum of the number of milliequivalents incorporated ionic groups per 100 g of polyurethane and the number at "pseudomilli equivalents" at built-in pendent ones Ethylene oxide units per 100 g of polyurethane at 20 to 120 and more preferably between 24 and 56th

Under a "Pseudomilliäquivalent" on pending or terminally incorporated ethylene oxide units here the amount of within a polyalkylene oxide Chain understood built-in ethylene oxide units be the dispersibility of the polyurethane in Water delivers the same amount as a milliequivalent on incorporated ionic groups. The effectiveness the above-mentioned ionic groups with respect their contribution to the dispersibility of the polyurethane depends solely on the number of milliequivalents ionic groups and not of the ionic type Groups off. In the aqueous polyurethane dispersions depends on the average particle diameter of the dispersed Polyurethane particles from the concentration of the built-in hydrophilic centers in the polyurethane. Sun rises in the general, the average particle size in otherwise analogous structure of the polyurethane with decreasing concentration at hydrophilic centers. As a result of incoming Studies of the applicant turned out, one can in any water-dispersible, exclusive ionically modified polyurethane in otherwise completely analogous molecular structure the ionic Groups always by a certain amount of lateral arranged within a polyether chain  Replace ethylene oxide so that a corresponding exclusive obtained nonionically modified polyurethane is in water-dispersed form the has the same average particle size, (wherein a analogous preparation of the polyurethane dispersion is assumed), if those in ionic modified Polyurethane present milliequivalent to ionic Groups by the same number of "pseudomillie equivalents" be replaced on nonionic groups. So correspond to one milliequivalent of incorporated ionic Groups 0.5 g lateral within one Polyether chain built-in ethylene oxide units. Under a "pseudomilli equivalent" to nonionic groups are therefore 0.5 g of lateral within a Polyether chain incorporated ethylene oxide units too understand. Accordingly, for example, an aqueous Dispersion of an exclusively ionically modified Polyurethane containing 16 milliequivalents per 100 g dispersed on one of said ionic groups Polyurethane particles with the same middle Particle diameter on like an analogously constructed and prepared exclusively nonionic modified Polyurethane dispersion containing 8 g per 100 g to ethylene oxide incorporated within a polyether chain.

The implementation of the method according to the invention for Preparation of self-dispersible polyurethanes can according to the known methods of polyurethane chemistry  both after the one-step and the two-step Procedure (prepolymer method) take place.

In the preparation of self-dispersible polyurethanes the reactants come in an equivalent ratio from isocyanate groups to isocyanate groups reactive groups of 0.8: 1 to 2.5: 1, preferably from 0.95: 1 to 1.5: 1 used. In the Use of an NCO excess naturally arise NCO group-containing compounds that are found in their conversion into an aqueous dispersion with the Water with chain extension to the dispersed Reactivate the final product. Accordingly includes the given equivalent ratio all at the construction of the Polyurethane according to the invention involved components including optionally in the form of aqueous solutions used amino-containing chain extender, but not the proportion of the dispersion the polyurethane used water, which having optionally present NCO groups Compounds under chain extension production react.

Both in the implementation of the single-stage and the Two-step procedure can be in presence or absence be worked by solvents. suitable Solvent, especially if - as below described - during or after the polyurethane production the transfer of the polyurethanes in one  aqueous dispersion is intended, for example water-miscible, indifferent to isocyanate groups Solvent with a lying below 100 ° C. Boiling point, such. As acetone or methyl ethyl ketone.

In carrying out the one-step process are preferred the difunctional ones mentioned under 1. to 7. terminal, isocyanate-reactive Group containing compounds of the molecular weight range from 500 to 6000 with the hydrophilic components a) and b) as well as, if applicable, to be used Chain extender of a lower than 300 Molecular weight mixed. The thus obtained Mixture is then the diisocyanate in the absence of solvents, after which the reaction mixture preferably at 50 to 150 ° C temperatures, optionally after addition of the in polyurethane chemistry known catalysts for the reaction is brought. The amount of diisocyanates is hereby chosen so that an NCO / OH ratio of 0.8 to 1.05 is present. During the reaction, the viscosity of the Reaction mixture, so that the mixture gradually one of said solvents is added. Finally, an organic solution of the reacted Polyurethane, their concentration preferably to 10 to 70, in particular 15 to 55 wt .-% Solid is set. In this one-step process In particular, the use of tertiary amines having 2 alcoholic hydroxyl groups as  Component b). If used as component b) compounds which are convertible into cationic groups Groups, this transfer is recommended by per se known neutralization or quaternization following the polyaddition reaction either in organic solution or in such a way that that in organic Solution present polyurethane during his Transfer into an aqueous dispersion by in the water present neutralizing agent is neutralized.

The transfer of the dissolved polyurethane elastomers in an aqueous dispersion is then expediently carried out by adding water to the stirred solution. there in many cases becomes the phase of a water-in-oil emulsion go through, after which, while overcoming a maximum viscosity of the envelope in one Oil-in-water emulsion yields. After distillative removal the solvent remains a purely aqueous stable dispersion back.

In carrying out the two-stage process is preferably initially in the melt from excess Diisocyanate, higher molecular weight compound with opposite Isocyanate groups reactive groups of less than 1. to 7. exemplified type and hydrophilic components a) and b) while maintaining an NCO / OH ratio from 1.1: 1 to 3.5: 1, preferably 1.2: 1 to 2.5: 1 in the absence of solvents or else already in the presence of solvents an NCO prepolymer prepared, which in the absence of solvents  then in a suitable solvent is recorded. The solution of the prepolymer thus obtained can then in a conventional manner with the Chain extenders exemplified Type of molecular weight below 300 for Be brought reaction. For the preparation of the polyurethane dispersions We recommend a special variant the two-stage process in which the described Solution of the NCO prepolymer with the solution of the chain extender - Here are the preferred Diamines or hydrazine derivatives as chain extenders used - in small quantities of water or in a water / solvent mixture is added, that the NCO / NH ratio is between 2.5 and 1.05. This reaction may be at room temperature or also preferably be carried out at 25 to 60 ° C. By subsequent Add the remaining water and then remove the solvent eventually becomes the polyurethane dispersion receive. It is in this process variant but also possible, the chain extender in the total amount in the dispersion eventually present water (50 to 200 wt .-%, based on solid polyurethane).

However, the described two-stage process can also carried out without major difficulties solvent-free become, in such a way that one describes the described Produces NCO prepolymers solvent-free and as Melt stirred into the water, where also mentioned Amino-containing chain extender may be in dissolved form in the water.  

The present invention can be prepared in water-dispersible Polyurethane elastomers are preferably predominantly Linear molecular structure and are by a Content of pendant or terminal of a polyether chain incorporated ethylene oxide of 2 to 10, preferably from 4 to 8 wt .-% and a content of = N⊕ = or -S⊕- Groups from 16 to 100, preferably from 16 to 40, Milliequivalent per 100 g. Preferably is the pendant polyalkylene oxide chain which is essential to the invention Having ethylene oxide units, about groupings

• i) the general formula or
• ii) the general formula connected, where
  R, R ", X and Y have the abovementioned meaning.

In principle, the invention can be produced Polyurethanes by any method in aqueous Dispersions are transferred. To mention here would be as examples the dispersion, without use of Solver, z. B. by mixing the polyurethane melt with water in devices that produce high shear rates can, as well as the use of very small quantities Solvents for plasticizing during processing in the same devices, continue to use non-mechanical dispersing agents, such as sound waves extremely high frequency. Finally, polyurethaneureas are also used the chain extension after the Transfer of prepolymers into an aqueous emulsion possible. However, it is also easy mixer, z. B. Stirred tank or so-called continuous mixer use find because the polyurethanes produced according to the invention are self-dispersible.

The dispersed polyurethanes prepared according to the invention have an average particle size of <300 mμ, preferably from 10 to 250 mμ.

This is the particle size range within it usual cationic dispersions the greatest sensitivity consists of electrolyte additives. The Dispersions are opaque to translucent and show pronounced Tyndalleffekt, especially when on about 10% solids content are diluted.  

The rheological behavior of the dispersions, on the individual should not be taken depends on the Particle size and concentration. At the transition to smaller particles, the viscosity increases, as well occurs below a size of about 100 mμ one increasingly higher yield point (Bingham body). unscathed this dependence increases the viscosity with increasing concentration in this class of Dispersions can be up to 65%, z. T. up to a size of 5 Pa.s.

The dispersions, despite their content of cationic Groups largely insensitive to electrolytes; this allows z. As the acid catalyzed crosslinking the latex particles with formaldehyde or formaldehyde derivatives; as is their pigmentation with electrolyte-active pigments or dyes possible.

The dispersions can be combined with other cationic or nonionic dispersions are blended as z. With polyvinyl acetate, polyethylene, polystyrene, Polybutadiene, polyvinyl chloride, polyacrylate and copolymer Plastic dispersions. Also the addition of known chemically non-fixed, preferably ionic emulsifiers is possible, but of course not mandatory.

Finally, fillers, plasticizers, Pigments, carbon black and silica sols, aluminum, clay, Asbestos dispersions incorporated into the dispersions become.  

The dispersions of polyurethanes in water are mostly Stable, storable and ready to ship and can be used as desired later date, z. B. shaping, processed. They generally dry immediately to dimensionally stable Plastic coatings on, however, the shape of the Process products also in the presence of known per se Crosslinking agents take place. Depending on the chosen chemical composition and content Urethane groups are obtained with polyurethanes with different Properties. So soft sticky masses, thermoplastic and rubber-elastic products of various kinds Hardness up to glass-hard thermosets to be obtained. The hydrophilicity of the products can also to fluctuate within certain limits. The elastic Products can be at higher temperatures, for example 100 to 180 ° C thermoplastic process, unless they are chemically crosslinked.

The process products are for coating or for Coating and impregnating of woven and non-woven Textiles, Leather, Paper, Wood, Metals, Ceramics, Stone, Concrete, Bitumen, Hardboard, Straw, Glass, Porcelain, plastics of various kinds, glass fibers, for antistatic and wrinkle-free equipment, as a binder for nonwovens, adhesives, adhesion promoters, laminating agents, Water repellents, plasticizers, Binders, e.g. Cork or wood flour, glass fibers, Asbestos, paper-like materials, plastic or rubber waste, ceramic materials, as auxiliaries in the Styria and in the paper industry, as an addition to  Polymers, as sizing agents, for example Glass fibers, and suitable for leather equipment.

Preferably, the dispersions or pastes are included applied to a porous pad, which subsequently remains connected to the finished product, such. B. woven or nonwoven textile structures or fiber mats, Felts or fleeces, also paper fleeces, foam foils or split leather, the assets of their suction instant Solidification of the coating effect. Subsequently is dried at elevated temperature and optionally pressed. The drying can also be on smooth porous or nonporous materials, e.g. B. Metal, glass, paper, cardboard, ceramic materials, Steel sheet, silicone rubber and aluminum foil, take place, the finished sheet subsequently lifted and used as such or by the inversion method by gluing, flame lamination, calendering is applied to a substrate. The application after The reversal process can be at any time be made.

By concomitant use of vinyl polymers or active or inactive fillers you can see the properties modify the process products. Usable are, for example Polyethylene, polypropylene, polyvinyl acetate, Ethylene-vinyl acetate copolymers, optionally (partially) saponified and / or grafted with vinyl chloride may be styrene-butadiene copolymers, ethylene (Graft) copolymers, polyacrylates, carbon black, silica,  Asbestos, talc, kaolin, titanium dioxide, glass powder or in the form of fibers and cellulose. Depending on the desired Property picture and purpose of the final products can be up to 70% by weight, based on the total dry matter, such fillers contained in the final product his.

Of course, dyes, pigments, Plasticizer or the rheological properties influencing Additions are attached.

The drying of various application techniques obtained products can at room temperature or be carried out at elevated temperature. Which in the individual case too choosing drying temperature, except from the chemical Composition of the material mainly of Moisture content, drying time and layer thickness depends, is easily determined by a pre-test. For a given heating time, the drying temperature in any case below the solidification temperature lie.

Subsequently, the fabrics can increase the resistance of their surface with a Finishing be coated. Preference will be this in turn, aqueous dispersions or solutions used.

Of finely divided dispersions and sols obtained very Hard polyurethanes are as baked enamels and partly even suitable as air-drying paints. They connect  high hardness and elasticity with good gloss and - at Use with aliphatic diisocyanates - with good Light and weather fastness.

The following examples are intended to describe the composition, Explain production and some physical properties.  

Example 1 a) Preparation of the lateral ethylene oxide units having hydrophilic chain extender

The lateral ethylene oxide units having hydrophilic chain extender is by analogy to the procedure described in US-PS 39 05 929 produced by implementation of equivalent divide

• (i) a polyether monoalcohol of n-butanol, Ethylene oxide and propylene oxide (in molar ratio 83: 17) of the OH number 30,
• (ii) hexane diisocyanate-1,6 and
• (Iii) diethanolamine.

The resulting diol has an average molecular weight from 2140 on.

b) Preparation of the cationic polyurethane dispersion

4970 parts by weight of a polyesterdiol of adipic acid, Phthalic anhydride and ethylene glycol of OH number 67, 16 580 parts by weight of a polyester diol from phthalic anhydride and ethylene glycol of OH Number 56 and 1350 parts by weight of the described under a)  Chain extenders become together in vacuo at 0.0195 bar 120 ° C, 30 minutes dewatered. After cooling to 80 ° C be 3377 parts by weight of 1,6-hexanediisocyanate at once added, stirred for 10 minutes without heating, then is stirred at 110 to 120 ° C for 45 minutes. you allowed to cool and diluted from 80 ° C carefully in portions with a total of 11,060 parts by weight of acetone. In the stirred at 60 ° C, slightly at reflux boiling acetonic solution become 500 parts by weight N-Methyldiethanolamin added and with 1580 wt. After rinsing with acetone, it is stirred for one hour at 60 ° C, adds 222 parts by weight of 1,2-diaminopropane, rinsed with 1580 parts by weight of acetone and diluted with a further 7110 parts by weight of acetone. The acetonic Solution is further stirred at 60 ° C. 30 Minutes after the amine addition, 100 parts by weight Water and 1 part by weight dibutyltin dilaurate was added and diluted with 10 270 parts by weight of acetone.

After 6 hours can be in the acetone solution No more isocyanate detected by IR spectroscopy. Add 500 parts by weight of dimethyl sulfate dissolved in 1580 parts by weight of acetone, stirred for 1 hour at 50 ° C. after and then leaves - also at 50 ° C - 36 000 parts by weight of water preheated to 50 ° C Run slowly within 30 minutes.  

After distilling off the acetone in a water jet pump Vacuum at 50 ° C is added 1500 parts by weight a 30% formalin solution and receives 60,000 parts by weight of a stable cationic polyurethane dispersion, at a solids content of 43% by weight, a pH of 4.2 and a particle size (Diameter determined by means of light scattering) of 142-149 nm.

The polyurethane contains 3.48% by weight of pendant built-in ethylene oxide units and 17.6 m Equivalent to

to 100 g of solids.

electrolyte stability

50 g of a set to 10 wt .-% solids Sample of this dispersion needed at room temperature 80 ml of a 10% NaCl solution for coagulation. A corresponding polyurethane dispersion, but without the nonionic-hydrophilic emulsifier prepared, coagulated under the same test conditions after the addition of 3.4 ml of NaCl Solution.  

c) General regulation for the determination of electrolyte stability cationic polyurethane dispersions

50 ml of a cationic adjusted to 10% solids Polyurethane dispersion are in one Erlenmeyer flask submitted and under vigorous Stir with a magnetic stirrer at room temperature dropwise from a storage burette with 10% aqueous NaCl solution. After increasing thickening occurs mostly abrupt coagulation of Dispersion on, at least at a consumption of Saline <20 ml. For even higher electrolyte stability prepares the final product determination sometimes trouble, since coagulation only hesitantly with partial flocculation occurs. In In this case, the end point determination is facilitated, if you take the saline in 5 ml portions added, after each addition stirred for 5 minutes and then make the assessment.

example 2

This example illustrates the dependence of electrolyte stability from the amount of ethylene oxide units used demonstrated.

• a) 86.3 parts by weight of a polyester diol of adipic acid, phthalic anhydride and ethylene glycol of OH number 67, 307.7 parts by weight of polyester diol from phthalic anhydride and ethylene glycol of OH number 56 and 17.2 parts by weight of a polyether monoalcohol from n-butanol, ethylene oxide and propylene oxide (in the molar ratio 83: 17) of the OH number 26 are combined and dehydrated at 0.0195 bar, 120 ° C for 30 minutes. After cooling to 80 ° C 67.2 parts by weight of 1,6-hexanediisocyanate are added, mixed without heating for 10 minutes and then stirred at 120 ° C for a further 110 minutes. The NCO content is determined (3.12%) and diluted with cooling to 60 ° C with 80 parts by weight of acetone, 11.9 parts by weight of N-methyldiethanolamine are added and stirred at 60 ° C for 1 hour, then is diluted with a further 80 parts by weight of acetone, successively 6.6 parts by weight of 1-aminomethyl-5-amino-1,3,3-trimethylcyclohexane and 1.94 parts by weight of hydrazine monohydrate are added, 30 minutes at 60 C., diluted with a further 160 parts by weight of acetone, 8.4 parts by weight of chloroacetamide are quaternized for 1 hour, 11 parts by weight of 85% strength o-phosphoric acid are added and finally 1125 parts by weight are left Water to give a finely divided, bluish translucent dispersion is formed after distilling off the acetone in vacuo (0.0195 bar, bath temperature 50 ° C) has a solids content of 30%, a pH of 4.2 and a mean particle diameter of 143 -174 nm. The dispersion is amazingly stable in temperature, it withstands a 24-hour annealing at 85 ° C without changing the particle size.
  At a content of 2.76% ethylene oxide units, based on polyurethane solids, and 22.7 milliequivalent for 100 g of solids, 50 ml of a 10% solids sample of this dispersion consume 5 ml of 10% aqueous saline until coagulation.
• b) According to Example 2a), a dispersion is prepared with the modification that the amount of hydrophilic Polyether is increased to 21.5 parts by weight and thus the content of ethylene oxide units based on polyurethane solid increased to 3.46% becomes. As a result, the electrolyte stability increases. 50 ml of a sample adjusted to 10% solids 2b) require 17.5 ml of one until coagulation 10% saline.
• c) According to Example 2b), a dispersion is prepared with the modification that the amount of hydrophilic Polyether is increased to 25.8 parts by weight and thus the content of ethylene oxide units increased to 4.08% based on polyurethane solids becomes. As a result, the electrolyte stability increases. 50 ml of a sample adjusted to 10% solids 2c) required 30 ml of one until coagulation 10% saline.  
• d) According to Example 2c), a dispersion is prepared with the modification that the amount of hydrophilic Polyether to 30 parts by weight, corresponding to 4.7% Ethylene oxide units based on polyurethane Solid, is raised. The electrolyte stability this increases. 50 ml one to 10% Solid sample 2d) required for Coagulation 70 ml of a 10% saline solution.

example 3

This example is used for dispersions of the same composition the dependence of the electrolyte stability shown by the particle size.

According to the method described in Example 2 Polyurethane dispersions from the following starting materials manufactured:

65 parts by weight Polyester diol from adipic acid, Phthalic anhydride and ethylene glycol, OH number 67 222.6 parts by weight Polyester diol from phthalic anhydride and ethylene glycol, OH number 56 16.7 parts by weight lateral ethylene oxide units having hydrophilic chain extender according to Example 1 50 parts by weight Hexane-1,6-diol 8.8 parts by weight methyldiethanolamine 5.7 parts by weight 1-Aminomethyl-5-amino-1,3,3-trimethylcyclohexane 1.6 parts by weight hydrazine monohydrate 6.2 parts by weight chloroacetamide 8 parts by weight o-phosphoric acid (85%) 844 parts by weight water

By varying the manufacturing conditions (time and Temperature variation in the graft polymer formation and Amount of solvent) were the same chemical composition Dispersions of different particle size receive. The polyurethane has 3.14% lateral Ethylene oxide units and 22.6 milliequivalent

per 100 g of solids.

Of these dispersions, the same was used in Example 1 specified method determines the electrolyte stability. The result is shown in Table 1.  

Table 1

example 4

340 parts by weight of a polyester diol of 1,6-hexanediol, 2,2-Dimethylpropandiol-1,3 and adipic acid of the OH number 65 and 21.5 parts by weight of a polyether monoalcohol of OH number 26 (according to Example 2) will be 30 minutes at a Dehydrated pressure of 0.0195 bar and a temperature of 120 ° C.  After cooling to 80 ° C 67.2 parts by weight Hexane diisocyanate-1,6 added, 30 minutes at 80 ° C and Stirred for 90 minutes at 120 ° C and then the NCO content of the prepolymer determined (3.53 wt .-% NCO). One lets Cool and dilute slowly from 80 ° C with 80 parts by weight Acetone. In the homogeneous solution (outside temperature 70 ° C) 9.5 parts by weight of N-methyldiethanolamine are added and Stirred for 1 hour, successively 8.5 parts by weight 1-aminomethyl-5-amino-1,3,3-trimethylcyclohexane and 2.5 parts by weight of hydrazine monohydrate added, one hour stirred at 70 ° C outside temperature, with a further 160 wt. Parts of acetone diluted and with 6.7 parts by weight of chloroacetamide added. After the IR spectrum of a sample no more NCO band, 11 g of o-phosphoric acid (85%) was added, then allowed Add 1100 parts by weight of heated water and distilled from the corresponding cationic polyurethane Dispersion the acetone in a water jet vacuum, wherein the bath temperature is kept at 50 ° C. The resulting stable dispersion indicates at a solids content of 31% by weight has an average particle diameter of 126-130 nm and a pH of 4.2. Related to Solid, the product contains 3.84% by weight of polyethylene oxide segments and 20.1 milliequivalents of quaternary nitrogen / 100 g of polyurethane.

50 ml of a sample adjusted to 10% solids This dispersion required 110 ml of 10% NaCl solution for coagulation (determination of electrolysis stability according to Example 1).

Claims (4)

1. A process for the preparation of water-dispersible polyurethanes having a substantially linear molecular structure by reacting organic diisocyanates with difunctional in the sense of Isocyanatopolyadditionsreaktion, terminal isocyanate-reactive hydrogen atoms having organic compounds in the molecular weight range from 300 to 6000 with the concomitant use of both

• a) diisocyanates and / or in the sense of Isocyanatpolyadditionsreaktion difunctional compounds with isocyanate-reactive hydrogen atoms and with pendant ethylene oxide units having hydrophilic chains in such an amount that in the final polyurethane obtained 2 to 10 wt .-% of lateral ethylene oxide units, as well
• b) mono- or diisocyanates and / or compounds which are mono- or difunctional in the sense of the isocyanate polyaddition reaction and which have isocyanate-reactive hydrogen atoms with ionic groups or groups which can be converted into ionic groups,

at least partial conversion of the latter groups into hydrophilic groups during or subsequent to the polyaddition reaction, and optionally with concomitant use of the chain extender known per se in polyurethane chemistry of less than 300 molecular weight in an equivalent ratio of isocyanate groups of 0.8: 1 to 2, 5: 1 and optionally with the concomitant use of customary in polyurethane chemistry auxiliaries and additives, characterized in that

• i) optionally in place of or together with the diisocyanates or difunctional compounds with isocyanate-reactive hydrogen atoms having pendent ethylene oxide units having hydrophilic chains, monoisocyanates having ethylene oxide units having hydrophilic chains and / or in the sense of isocyanate polyaddition reaction to isocyanate-reactive hydrogen atoms with ethylene oxide units having hydrophilic chains in one used in such an amount that in the final polyurethane obtained 2 to 10 wt .-% terminally incorporated or 2 to 10 wt .-% side or terminal incorporated ethylene oxide units, and that
• ii) the type and amount or the degree of neutralization or quaternization of component b) is such that in the final polyurethane obtained from 16 to 100 milliequivalents per 100 g available.

2. The method according to claim 1, characterized in that as a component

• a) a diol of the general formula is used, in which
  R is a divalent radical as obtained by removing the isocyanate groups from a diisocyanate having a molecular weight of 112 to 1000,
  R 'is hydrogen or a monovalent hydrocarbon radical having 1 to 8 carbon atoms,
  X is a divalent polyalkylene oxide radical having 5 to 90 alkylene oxide units, in which at least 40% of these alkylene oxide units are ethylene oxide units and the remaining alkylene oxide units are propylene oxide, butylene oxide or styrene oxide units,
  Y is oxygen or a -NR '''- radical is and
  R '' and R '''are the same or different and represent a monovalent hydrocarbon radical having 1 to 12 carbon atoms.

3. The method according to claim 1, characterized that as component a) a monofunctional polyether the general formula H-X-Y-R "is used, in the X, Y and R" in claim 2 have meaning indicated.